Audio mixing is an extremely important part of the music creation and recording process. Many different vocals and instruments are mixed together to create a single work. Each instrument and audio track has various dynamics and frequency ranges that are combined to create the final piece in the mixing and recording process. Different sounds can be amplified or reduced in order to create the final piece. To do so, filtering equipment, such as graphic equalizers, have been developed that allow mixers to increase or decrease the amplitude of different frequencies of the audio track. For example, a saxophone will have different frequency ranges than will vocals. By adjusting the amplitude of the frequencies through which the different audio signals pass, the overall sound of the song will be changed. Such equalizer designs are disclosed in U.S. Pat. Nos. 5,805,716 and 5,748,754, both of which are incorporated herein by reference.
While audio mixing has been around for many years, there are some limitations as to how much of the song can be changed without degrading the overall quality of the audio signal. Vocals and other audio signals in the 2.5 kHz band range can be harsh to the human ear and may need to be compressed dynamically to create a strong, but not overpowering sound.
Therefore, what is needed is a low phase shift equalization circuit and design that allows high-frequency sounds to be compressed independently of other frequencies.